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<a href="optional_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno">    1</span>&#160;<span class="comment">/** \file jsonv/optional.hpp</span></div><div class="line"><a name="l00002"></a><span class="lineno">    2</span>&#160;<span class="comment"> *  Pulls in an implementation of \c optional.</span></div><div class="line"><a name="l00003"></a><span class="lineno">    3</span>&#160;<span class="comment"> *  </span></div><div class="line"><a name="l00004"></a><span class="lineno">    4</span>&#160;<span class="comment"> *  Copyright (c) 2016 by Travis Gockel. All rights reserved.</span></div><div class="line"><a name="l00005"></a><span class="lineno">    5</span>&#160;<span class="comment"> *</span></div><div class="line"><a name="l00006"></a><span class="lineno">    6</span>&#160;<span class="comment"> *  This program is free software: you can redistribute it and/or modify it under the terms of the Apache License</span></div><div class="line"><a name="l00007"></a><span class="lineno">    7</span>&#160;<span class="comment"> *  as published by the Apache Software Foundation, either version 2 of the License, or (at your option) any later</span></div><div class="line"><a name="l00008"></a><span class="lineno">    8</span>&#160;<span class="comment"> *  version.</span></div><div class="line"><a name="l00009"></a><span class="lineno">    9</span>&#160;<span class="comment"> *</span></div><div class="line"><a name="l00010"></a><span class="lineno">   10</span>&#160;<span class="comment"> *  \author Travis Gockel (travis@gockelhut.com)</span></div><div class="line"><a name="l00011"></a><span class="lineno">   11</span>&#160;<span class="comment">**/</span></div><div class="line"><a name="l00012"></a><span class="lineno">   12</span>&#160;<span class="preprocessor">#ifndef __JSONV_OPTIONAL_HPP_INCLUDED__</span></div><div class="line"><a name="l00013"></a><span class="lineno">   13</span>&#160;<span class="preprocessor">#define __JSONV_OPTIONAL_HPP_INCLUDED__</span></div><div class="line"><a name="l00014"></a><span class="lineno">   14</span>&#160;</div><div class="line"><a name="l00015"></a><span class="lineno">   15</span>&#160;<span class="preprocessor">#include &lt;<a class="code" href="config_8hpp.html">jsonv/config.hpp</a>&gt;</span></div><div class="line"><a name="l00016"></a><span class="lineno">   16</span>&#160;</div><div class="line"><a name="l00017"></a><span class="lineno">   17</span>&#160;<span class="preprocessor">#ifndef JSONV_OPTIONAL_USE_STD</span></div><div class="line"><a name="l00018"></a><span class="lineno">   18</span>&#160;<span class="preprocessor">#   define JSONV_OPTIONAL_USE_STD 0</span></div><div class="line"><a name="l00019"></a><span class="lineno">   19</span>&#160;<span class="preprocessor">#endif</span></div><div class="line"><a name="l00020"></a><span class="lineno">   20</span>&#160;</div><div class="line"><a name="l00021"></a><span class="lineno">   21</span>&#160;<span class="preprocessor">#ifndef JSONV_OPTIONAL_USE_STD_EXPERIMENTAL</span></div><div class="line"><a name="l00022"></a><span class="lineno">   22</span>&#160;<span class="preprocessor">#   define JSONV_OPTIONAL_USE_STD_EXPERIMENTAL 0</span></div><div class="line"><a name="l00023"></a><span class="lineno">   23</span>&#160;<span class="preprocessor">#endif</span></div><div class="line"><a name="l00024"></a><span class="lineno">   24</span>&#160;</div><div class="line"><a name="l00025"></a><span class="lineno">   25</span>&#160;<span class="preprocessor">#ifndef JSONV_OPTIONAL_USE_BOOST</span></div><div class="line"><a name="l00026"></a><span class="lineno">   26</span>&#160;<span class="preprocessor">#   define JSONV_OPTIONAL_USE_BOOST 0</span></div><div class="line"><a name="l00027"></a><span class="lineno">   27</span>&#160;<span class="preprocessor">#endif</span></div><div class="line"><a name="l00028"></a><span class="lineno">   28</span>&#160;</div><div class="line"><a name="l00029"></a><span class="lineno">   29</span>&#160;<span class="comment">// Attempt to guess between JSONV_OPTIONAL_USE_STD and JSONV_OPTIONAL_USE_STD_EXPERIMENTAL based on C++ language version</span></div><div class="line"><a name="l00030"></a><span class="lineno">   30</span>&#160;<span class="preprocessor">#if !defined(JSONV_OPTIONAL_TYPE) &amp;&amp; !JSONV_OPTIONAL_USE_STD &amp;&amp; !JSONV_OPTIONAL_USE_STD_EXPERIMENTAL &amp;&amp; !JSONV_OPTIONAL_USE_BOOST</span></div><div class="line"><a name="l00031"></a><span class="lineno">   31</span>&#160;<span class="preprocessor">#   if __cplusplus &gt; 201700L</span></div><div class="line"><a name="l00032"></a><span class="lineno">   32</span>&#160;<span class="preprocessor">#       undef  JSONV_OPTIONAL_USE_STD</span></div><div class="line"><a name="l00033"></a><span class="lineno">   33</span>&#160;<span class="preprocessor">#       define JSONV_OPTIONAL_USE_STD 1</span></div><div class="line"><a name="l00034"></a><span class="lineno">   34</span>&#160;<span class="preprocessor">#   else</span></div><div class="line"><a name="l00035"></a><span class="lineno">   35</span>&#160;<span class="preprocessor">#       undef  JSONV_OPTIONAL_USE_STD_EXPERIMENTAL</span></div><div class="line"><a name="l00036"></a><span class="lineno">   36</span>&#160;<span class="preprocessor">#       define JSONV_OPTIONAL_USE_STD_EXPERIMENTAL 1</span></div><div class="line"><a name="l00037"></a><span class="lineno">   37</span>&#160;<span class="preprocessor">#   endif</span></div><div class="line"><a name="l00038"></a><span class="lineno">   38</span>&#160;<span class="preprocessor">#endif</span></div><div class="line"><a name="l00039"></a><span class="lineno">   39</span>&#160;<span class="comment"></span></div><div class="line"><a name="l00040"></a><span class="lineno">   40</span>&#160;<span class="comment">/** \def JSONV_OPTIONAL_TYPE</span></div><div class="line"><a name="l00041"></a><span class="lineno">   41</span>&#160;<span class="comment"> *  The type to use for \c jsonv::optional. By default, this is \c std::optional or \c std::experimental::optional,</span></div><div class="line"><a name="l00042"></a><span class="lineno">   42</span>&#160;<span class="comment"> *  depending on the C++ language version you are compiling with.</span></div><div class="line"><a name="l00043"></a><span class="lineno">   43</span>&#160;<span class="comment"> *  </span></div><div class="line"><a name="l00044"></a><span class="lineno">   44</span>&#160;<span class="comment"> *  \def JSONV_NULLOPT_VALUE</span></div><div class="line"><a name="l00045"></a><span class="lineno">   45</span>&#160;<span class="comment"> *  The value to use for \c jsonv::nullopt By default, this is \c std::nullopt or \c std::experimental::nullopt (by the</span></div><div class="line"><a name="l00046"></a><span class="lineno">   46</span>&#160;<span class="comment"> *  same rules as \c JSONV_OPTIONAL_TYPE). If you define \c JSONV_OPTIONAL_TYPE, you must also define this.</span></div><div class="line"><a name="l00047"></a><span class="lineno">   47</span>&#160;<span class="comment"> *  </span></div><div class="line"><a name="l00048"></a><span class="lineno">   48</span>&#160;<span class="comment"> *  \def JSONV_OPTIONAL_INCLUDE</span></div><div class="line"><a name="l00049"></a><span class="lineno">   49</span>&#160;<span class="comment"> *  The file to include to get the implementation for \c optional. If you define \c JSONV_OPTIONAL_TYPE, you must</span></div><div class="line"><a name="l00050"></a><span class="lineno">   50</span>&#160;<span class="comment"> *  also define this.</span></div><div class="line"><a name="l00051"></a><span class="lineno">   51</span>&#160;<span class="comment"> *  </span></div><div class="line"><a name="l00052"></a><span class="lineno">   52</span>&#160;<span class="comment"> *  \def JSONV_OPTIONAL_USE_STD</span></div><div class="line"><a name="l00053"></a><span class="lineno">   53</span>&#160;<span class="comment"> *  Set this to 1 to use \c std::optional as the backing type for \c jsonv::optional.</span></div><div class="line"><a name="l00054"></a><span class="lineno">   54</span>&#160;<span class="comment"> *  </span></div><div class="line"><a name="l00055"></a><span class="lineno">   55</span>&#160;<span class="comment"> *  \def JSONV_OPTIONAL_USE_STD_EXPERIMENTAL</span></div><div class="line"><a name="l00056"></a><span class="lineno">   56</span>&#160;<span class="comment"> *  Set this to 1 to use \c std::experimental::optional as the backing type for \c jsonv::optional.</span></div><div class="line"><a name="l00057"></a><span class="lineno">   57</span>&#160;<span class="comment"> *  </span></div><div class="line"><a name="l00058"></a><span class="lineno">   58</span>&#160;<span class="comment"> *  \def JSONV_OPTIONAL_USE_BOOST</span></div><div class="line"><a name="l00059"></a><span class="lineno">   59</span>&#160;<span class="comment"> *  Set this to 1 to use \c boost::optional as the backing type for \c jsonv::optional.</span></div><div class="line"><a name="l00060"></a><span class="lineno">   60</span>&#160;<span class="comment">**/</span></div><div class="line"><a name="l00061"></a><span class="lineno">   61</span>&#160;<span class="preprocessor">#ifndef JSONV_OPTIONAL_TYPE</span></div><div class="line"><a name="l00062"></a><span class="lineno">   62</span>&#160;<span class="preprocessor">#   if defined(JSONV_OPTIONAL_USE_STD_EXPERIMENTAL) &amp;&amp; JSONV_OPTIONAL_USE_STD_EXPERIMENTAL</span></div><div class="line"><a name="l00063"></a><span class="lineno"><a class="line" href="optional_8hpp.html#ae99aa4dea58bd0d958914ccdefce3b4d">   63</a></span>&#160;<span class="preprocessor">#       define JSONV_OPTIONAL_TYPE    std::experimental::optional</span></div><div class="line"><a name="l00064"></a><span class="lineno"><a class="line" href="optional_8hpp.html#ac7c5f430000395da6aa3fc7e7c568358">   64</a></span>&#160;<span class="preprocessor">#       define JSONV_NULLOPT_VALUE    std::experimental::nullopt</span></div><div class="line"><a name="l00065"></a><span class="lineno"><a class="line" href="optional_8hpp.html#a267d8a9738812252edfa0ae300ddaaf0">   65</a></span>&#160;<span class="preprocessor">#       define JSONV_OPTIONAL_INCLUDE &lt;experimental/optional&gt;</span></div><div class="line"><a name="l00066"></a><span class="lineno">   66</span>&#160;<span class="preprocessor">#   elif defined(JSONV_OPTIONAL_USE_BOOST) &amp;&amp; JSONV_OPTIONAL_USE_BOOST</span></div><div class="line"><a name="l00067"></a><span class="lineno">   67</span>&#160;<span class="preprocessor">#       define JSONV_OPTIONAL_TYPE    boost::optional</span></div><div class="line"><a name="l00068"></a><span class="lineno">   68</span>&#160;<span class="preprocessor">#       define JSONV_NULLOPT_VALUE    boost::none</span></div><div class="line"><a name="l00069"></a><span class="lineno">   69</span>&#160;<span class="preprocessor">#       define JSONV_OPTIONAL_INCLUDE &lt;boost/optional.hpp&gt;</span></div><div class="line"><a name="l00070"></a><span class="lineno">   70</span>&#160;<span class="preprocessor">#   else</span></div><div class="line"><a name="l00071"></a><span class="lineno">   71</span>&#160;<span class="preprocessor">#       define JSONV_OPTIONAL_TYPE    std::optional</span></div><div class="line"><a name="l00072"></a><span class="lineno">   72</span>&#160;<span class="preprocessor">#       define JSONV_NULLOPT_VALUE    std::nullopt</span></div><div class="line"><a name="l00073"></a><span class="lineno">   73</span>&#160;<span class="preprocessor">#       define JSONV_OPTIONAL_INCLUDE &lt;optional&gt;</span></div><div class="line"><a name="l00074"></a><span class="lineno">   74</span>&#160;<span class="preprocessor">#   endif</span></div><div class="line"><a name="l00075"></a><span class="lineno">   75</span>&#160;<span class="preprocessor">#endif</span></div><div class="line"><a name="l00076"></a><span class="lineno">   76</span>&#160;</div><div class="line"><a name="l00077"></a><span class="lineno">   77</span>&#160;<span class="preprocessor">#include JSONV_OPTIONAL_INCLUDE</span></div><div class="line"><a name="l00078"></a><span class="lineno">   78</span>&#160;</div><div class="line"><a name="l00079"></a><span class="lineno">   79</span>&#160;<span class="keyword">namespace </span><a class="code" href="namespacejsonv.html">jsonv</a></div><div class="line"><a name="l00080"></a><span class="lineno">   80</span>&#160;{</div><div class="line"><a name="l00081"></a><span class="lineno">   81</span>&#160;<span class="comment"></span></div><div class="line"><a name="l00082"></a><span class="lineno">   82</span>&#160;<span class="comment">/** Represents a value that may or may not be present.</span></div><div class="line"><a name="l00083"></a><span class="lineno">   83</span>&#160;<span class="comment"> *  </span></div><div class="line"><a name="l00084"></a><span class="lineno">   84</span>&#160;<span class="comment"> *  \see http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2012/n3442.html</span></div><div class="line"><a name="l00085"></a><span class="lineno">   85</span>&#160;<span class="comment">**/</span></div><div class="line"><a name="l00086"></a><span class="lineno">   86</span>&#160;<span class="keyword">template</span> &lt;<span class="keyword">typename</span> T&gt;</div><div class="line"><a name="l00087"></a><span class="lineno"><a class="line" href="optional_8hpp.html#a2cc4dac7916d509b758e598cb13d3130">   87</a></span>&#160;<span class="keyword">using</span> <a class="code" href="optional_8hpp.html#a2cc4dac7916d509b758e598cb13d3130">optional</a> = JSONV_OPTIONAL_TYPE&lt;T&gt;;</div><div class="line"><a name="l00088"></a><span class="lineno">   88</span>&#160;</div><div class="line"><a name="l00089"></a><span class="lineno">   89</span>&#160;<span class="keyword">namespace</span></div><div class="line"><a name="l00090"></a><span class="lineno">   90</span>&#160;{</div><div class="line"><a name="l00091"></a><span class="lineno">   91</span>&#160;</div><div class="line"><a name="l00092"></a><span class="lineno">   92</span>&#160;constexpr <span class="keyword">auto</span>&amp; nullopt <a class="code" href="config_8hpp.html#a7020e97cfeefd77fd7ad1d70f315dd49">JSONV_UNUSED</a> = <a class="code" href="optional_8hpp.html#ac7c5f430000395da6aa3fc7e7c568358">JSONV_NULLOPT_VALUE</a>;</div><div class="line"><a name="l00093"></a><span class="lineno">   93</span>&#160;</div><div class="line"><a name="l00094"></a><span class="lineno">   94</span>&#160;}</div><div class="line"><a name="l00095"></a><span class="lineno">   95</span>&#160;</div><div class="line"><a name="l00096"></a><span class="lineno">   96</span>&#160;}</div><div class="line"><a name="l00097"></a><span class="lineno">   97</span>&#160;</div><div class="line"><a name="l00098"></a><span class="lineno">   98</span>&#160;<span class="preprocessor">#endif</span><span class="comment">/*__JSONV_OPTIONAL_HPP_INCLUDED__*/</span><span class="preprocessor"></span></div><div class="ttc" id="config_8hpp_html"><div class="ttname"><a href="config_8hpp.html">config.hpp</a></div><div class="ttdoc">Copyright (c) 2014-2016 by Travis Gockel. </div></div>
<div class="ttc" id="optional_8hpp_html_ac7c5f430000395da6aa3fc7e7c568358"><div class="ttname"><a href="optional_8hpp.html#ac7c5f430000395da6aa3fc7e7c568358">JSONV_NULLOPT_VALUE</a></div><div class="ttdeci">#define JSONV_NULLOPT_VALUE</div><div class="ttdoc">The value to use for jsonv::nullopt By default, this is std::nullopt or std::experimental::nullopt (b...</div><div class="ttdef"><b>Definition:</b> <a href="optional_8hpp_source.html#l00064">optional.hpp:64</a></div></div>
<div class="ttc" id="config_8hpp_html_a7020e97cfeefd77fd7ad1d70f315dd49"><div class="ttname"><a href="config_8hpp.html#a7020e97cfeefd77fd7ad1d70f315dd49">JSONV_UNUSED</a></div><div class="ttdeci">#define JSONV_UNUSED</div><div class="ttdoc">Note that you know the variable is unused, but make the compiler stop complaining about it...</div><div class="ttdef"><b>Definition:</b> <a href="config_8hpp_source.html#l00115">config.hpp:115</a></div></div>
<div class="ttc" id="namespacejsonv_html"><div class="ttname"><a href="namespacejsonv.html">jsonv</a></div><div class="ttdef"><b>Definition:</b> <a href="algorithm_8hpp_source.html#l00023">algorithm.hpp:23</a></div></div>
<div class="ttc" id="optional_8hpp_html_a2cc4dac7916d509b758e598cb13d3130"><div class="ttname"><a href="optional_8hpp.html#a2cc4dac7916d509b758e598cb13d3130">jsonv::optional</a></div><div class="ttdeci">JSONV_OPTIONAL_TYPE&lt; T &gt; optional</div><div class="ttdoc">Represents a value that may or may not be present. </div><div class="ttdef"><b>Definition:</b> <a href="optional_8hpp_source.html#l00087">optional.hpp:87</a></div></div>
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